A mesoscale convective system/derecho developed in western Minnesota during the early morning, then tracked into central Wisconsin before riding the warm front southeast into southeast Wisconsin and portions of south-central Wisconsin during the afternoon.  The powerful winds generated by the storms were generally in the 52 to 56 knot range (60 to 65 mph), but peaked at hurricane-force in a couple locations .  Most of the damage was characterized as toppled large trees and downed power lines as the storms raced southeast.  The hardest hit areas were in Marquette, Dodge, and Jefferson counties.  Widespread tree damage was reported by law enforcement in Green Lake and southern Jefferson counties.  Otherwise damaging thunderstorm winds were more scattered.  A barn was completely destroyed 3 miles southwest of Waupun at 1405CST where winds were estimated to have gusted around 65 knots (75 mph).  Roof damage was noted on a house in Fox Lake (Dodge Co.), where winds were estimated to have gusted to around 65 knots (75 mph).  As the northeastern end of the line progressed toward the Lake Michigan shoreline, it weakened substantially.  However, the southwestern portion of the line progressed into Walworth, Racine, and Kenosha counties, continuing to produce areas of wind damage, before it died at the Illinois border shortly after 1530CST.  Lightning during the afternoon and overnight hours damaged two buildings in Watertown (Jefferson Co.).  Synoptically, the quasi-stationary front, noted in the July 21st episode, sagged south into Iowa and Illinois on the 22nd, then began to head back into Wisconsin as a warm front on the 23rd.

Thunderstorm Wind in MARQUETTE, WISCONSIN
From 23-JUL-05 13:26:00 to 23-JUL-05 13:26:00 (CST)
Location: WESTFIELD
Magnitude: 52 EG
Property damage: 1K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in DANE, WISCONSIN
From 23-JUL-05 14:20:00 to 23-JUL-05 14:20:00 (CST)
Location: MIDDLETON
Magnitude: 52 EG
Property damage: 2K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in WAUKESHA, WISCONSIN
From 23-JUL-05 14:50:00 to 23-JUL-05 14:50:00 (CST)
Location: HARTLAND
Magnitude: 52 EG
Property damage: 1K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in DODGE, WISCONSIN
From 23-JUL-05 14:10:00 to 23-JUL-05 14:10:00 (CST)
Location: ATWATER
Magnitude: 52 EG
Property damage: 1K
Reported by: AMATEUR RADIO

Thunderstorm Wind in DODGE, WISCONSIN
From 23-JUL-05 14:05:00 to 23-JUL-05 14:05:00 (CST)
Location: BEAVER DAM
Magnitude: 52 EG
Property damage: 2K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in SAUK, WISCONSIN
From 23-JUL-05 13:35:00 to 23-JUL-05 13:35:00 (CST)
Location: BARABOO
Magnitude: 52 EG
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in WALWORTH, WISCONSIN
From 23-JUL-05 15:02:00 to 23-JUL-05 15:02:00 (CST)
Location: SPRING PRAIRIE
Magnitude: 56 EG
Property damage: 3K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in COLUMBIA, WISCONSIN
From 23-JUL-05 14:30:00 to 23-JUL-05 14:30:00 (CST)
Location: FALL RIVER
Magnitude: 52 EG
Property damage: 2K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in GREEN LAKE, WISCONSIN
From 23-JUL-05 13:35:00 to 23-JUL-05 13:50:00 (CST)
Location: COUNTYWIDE
Magnitude: 56 EG
Property damage: 50K
Reported by: LAW ENFORCEMENT

Widespread tree damage and power-line damage reported across the county.

Thunderstorm Wind in DODGE, WISCONSIN
From 23-JUL-05 14:25:00 to 23-JUL-05 14:25:00 (CST)
Location: RICHWOOD
Magnitude: 52 EG
Property damage: 1K
Reported by: NWS STORM SURVEY

Thunderstorm Wind in WALWORTH, WISCONSIN
From 23-JUL-05 15:02:00 to 23-JUL-05 15:02:00 (CST)
Location: EAST TROY
Magnitude: 56 EG
Property damage: 5K
Reported by: TRAINED SPOTTER

Hail in WALWORTH, WISCONSIN
From 23-JUL-05 15:07:00 to 23-JUL-05 15:07:00 (CST)
Location: EAST TROY
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Hail in SAUK, WISCONSIN
From 23-JUL-05 12:23:00 to 23-JUL-05 12:23:00 (CST)
Location: MERRIMAC
Magnitude: 0.75 
Reported by: GENERAL PUBLIC

Thunderstorm Wind in KENOSHA, WISCONSIN
From 23-JUL-05 15:24:00 to 23-JUL-05 15:24:00 (CST)
Location: NEW MUNSTER
Magnitude: 52 EG
Property damage: 1K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in WALWORTH, WISCONSIN
From 23-JUL-05 15:02:00 to 23-JUL-05 15:02:00 (CST)
Location: LA GRANGE
Magnitude: 52 EG
Property damage: 3K
Reported by: GENERAL PUBLIC

Lightning in JEFFERSON, WISCONSIN
From 23-JUL-05 21:30:00 to 23-JUL-05 21:30:00 (CST)
Location: WATERTOWN
Property damage: 100K
Reported by: NEWSPAPER

Thunderstorm Wind in KENOSHA, WISCONSIN
From 23-JUL-05 15:24:00 to 23-JUL-05 15:24:00 (CST)
Location: SILVER LAKE
Magnitude: 52 EG
Property damage: 1K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in COLUMBIA, WISCONSIN
From 23-JUL-05 13:40:00 to 23-JUL-05 13:50:00 (CST)
Location: PORTAGE
Magnitude: 56 EG
Property damage: 10K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in ROCK, WISCONSIN
From 23-JUL-05 14:52:00 to 23-JUL-05 14:52:00 (CST)
Location: MILTON
Magnitude: 56 EG
Property damage: 1K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in JEFFERSON, WISCONSIN
From 23-JUL-05 14:30:00 to 23-JUL-05 14:45:00 (CST)
Location: FT ATKINSON
Magnitude: 58 MG
Property damage: 30K
Reported by: OFFICIAL NWS OBS.

Thunderstorm Wind in FOND DU LAC, WISCONSIN
From 23-JUL-05 13:55:00 to 23-JUL-05 13:55:00 (CST)
Location: BRANDON
Magnitude: 56 EG
Property damage: 5K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in KENOSHA, WISCONSIN
From 23-JUL-05 15:32:00 to 23-JUL-05 15:32:00 (CST)
Location: SILVER LAKE
Magnitude: 52 EG
Property damage: 1K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in ROCK, WISCONSIN
From 23-JUL-05 14:47:00 to 23-JUL-05 14:47:00 (CST)
Location: MILTON
Magnitude: 56 EG
Property damage: 1K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in FOND DU LAC, WISCONSIN
From 23-JUL-05 14:11:00 to 23-JUL-05 14:11:00 (CST)
Location: ROSENDALE
Magnitude: 52 EG
Property damage: 1K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in COLUMBIA, WISCONSIN
From 23-JUL-05 14:40:00 to 23-JUL-05 14:40:00 (CST)
Location: COLUMBUS
Magnitude: 56 EG
Property damage: 20K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in WAUKESHA, WISCONSIN
From 23-JUL-05 15:00:00 to 23-JUL-05 15:00:00 (CST)
Location: MUKWONAGO
Magnitude: 52 EG
Property damage: 1K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in DODGE, WISCONSIN
From 23-JUL-05 14:05:00 to 23-JUL-05 14:05:00 (CST)
Location: WAUPUN
Magnitude: 65 EG
Property damage: 50K
Reported by: GENERAL PUBLIC

Barn blown down.

Thunderstorm Wind in RACINE, WISCONSIN
From 23-JUL-05 15:24:00 to 23-JUL-05 15:24:00 (CST)
Location: BURLINGTON
Magnitude: 52 EG
Property damage: 1K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in KENOSHA, WISCONSIN
From 23-JUL-05 15:26:00 to 23-JUL-05 15:26:00 (CST)
Location: SILVER LAKE
Magnitude: 52 EG
Property damage: 1K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in MARQUETTE, WISCONSIN
From 23-JUL-05 13:30:00 to 23-JUL-05 13:30:00 (CST)
Location: MONTELLO
Magnitude: 56 EG
Property damage: 3K
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in WALWORTH, WISCONSIN
From 23-JUL-05 15:06:00 to 23-JUL-05 15:06:00 (CST)
Location: WHITEWATER
Magnitude: 52 MG
Property damage: 1K
Reported by: TRAINED SPOTTER

Lightning in JEFFERSON, WISCONSIN
From 23-JUL-05 14:35:00 to 23-JUL-05 14:35:00 (CST)
Location: WATERTOWN
Property damage: 1K
Reported by: FIRE DEPT/RESCUE SQUAD

Thunderstorm Wind in WAUKESHA, WISCONSIN
From 23-JUL-05 14:55:00 to 23-JUL-05 14:55:00 (CST)
Location: DOUSMAN
Magnitude: 52 EG
Property damage: 1K
Reported by: NWS EMPLOYEE(OFF DUTY)

Thunderstorm Wind in DODGE, WISCONSIN
From 23-JUL-05 14:03:00 to 23-JUL-05 14:03:00 (CST)
Location: FOX LAKE
Magnitude: 65 EG
Property damage: 5K
Reported by: GENERAL PUBLIC

Roof damage to a house.

Thunderstorm Wind in WALWORTH, WISCONSIN
From 23-JUL-05 15:21:00 to 23-JUL-05 15:21:00 (CST)
Location: EAST TROY
Magnitude: 56 EG
Reported by: GENERAL PUBLIC

Thunderstorm Wind in RACINE, WISCONSIN
From 23-JUL-05 15:29:00 to 23-JUL-05 15:29:00 (CST)
Location: BURLINGTON
Magnitude: 56 EG
Property damage: 3K
Reported by: GENERAL PUBLIC